Theories: theories are statement systems for the explanation of observations, e.g. of behavior or physical, chemical or biological processes. When setting up theories, a subject domain, a vocabulary of the terms to be used and admissible methods of observation are defined. In addition to explanations, the goal of the theory formation is the predictability and comparability of observations. See also systems, models, experiments, observation, observation language, theoretical terms, theoretical entities, predictions, analogies, comparisons, evidence, verification, reduction, definitions, definability._____________Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments.

I 3
Theory/Science/Fraassen: Fraassen also tries to find an explanation for unobservable processes which explains the observable and also merely possible processes.
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I 4
Theories/Fraassen: a theory must preserve the phenomena, i.e. describe correctly. - Then "accepting the theory" means believing that it is true.
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I 43f
Theory/Semantics/Syntax/Fraassen: Evaluate theories better semantically (e.g., via models) rather than syntactically.
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I 44
Syntactic: takes theory as a corpus of theorems. - there is a certain language for this theory. - semantic: class of structures or models. - Language is not fundamental here! - (s) Are isomorphic theories then semantically identical? - Fraassen: in other languages, the theories have other limitations, - This is about models, not about the language - e.g. Bohr's atom modell does not refer to a single structure, but to a single structure type - for example, hydrogen and helium atoms, etc. (class of structures, model type).
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I 48
Theory/Fraassen: different theories must have different empirical meaning (empirical import). - N.B.: even false theories can be empirically adequate.
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I 49
Maxwell/Hertz: Maxwell's theory is his equations. - I.e. it is not a mechanical theory, but it has mechanical models - N.B.: the electromagnetic forces depend on velocities, not just on acceleration.
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I 59
Theory/Unobservable/Fraassen: a physical theory cannot be translated without a rest into a corpus of sentences, which only states observable phenomena. - It must always take the unobserved into account.
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I 67
Theory/Fraassen: two groups:
1. Tarski-Suppes: set theoretically, extensionalist (FraassenVs)
2. Weyl-Evert Beth: state space, modal approach (Fraassen pro) - both initially designed language-dependent, later Vs)._____________Explanation of symbols: Roman numerals
indicate the source, arabic numerals indicate
the page number. The corresponding books
are indicated on the right hand side.
((s)…): Comment by the sender of the contribution.